Stereo phonograph cartridge



Aug. 16, 1966 R. DALLY STEREO PHONOGRAPH CARTRIDGE 2 Sheets-Sheet 1 Filed Nov. 1 1963 H INVENTOR- ROY DALLY,

HIS ATTORNEY.

Aug. 16, 1966 R. DALLY STEREO PHONOGRAPH CARTRIDGE 2 Sheets-Sheet 2 Filed Nov.

FIG3

FIGA

INVENTOR ROY DALLY,

BY HIS ATTORNEY.

FIGS

, phonic signals.

" 3,266,808 Patented August 16, 1966 3,266,808 STEREO PHONOGRAPH CARTRIDGE Roy Dally, Warreusburg, lll., assignor to General Electric Company, a corporation of New York Filed Nov. 1, 1963, Ser. No. 320,815

7 Claims. (Cl. 274-26) This invention relates to stereo phonograph pickup cartridges and in particular to the type of stereo pickupcartridges which employ transducer elements.

A well known type of stereo phonograph cartridge employs a pair of elongated ceramic transducer eleelements and coupler in the cartridge, one or more of the stereophonic signals received from the respective walls of the record groove might undesirably impart vibratory motion to both of the ceramic elements, thereby adversely effecting the separation of the two stereo- Accordingly, it is an important object of my invention to provide a stereo phonograph pickup cartridge which employs a novel means for effectively separating the stereophonic signals.

Another object of my invention is to provide an im- 'ments arranged within a housing with their longitudinal Referring in detail to the drawings, and in particular to FIGS. 1 and 2, there is shown a ceramic stereo pickup cartridge 11 which comprises a housing 13 composed of an uppercover part 15, a lower body 17, and end terminal board 19. j The three parts 15, 17 and 19 are secured by screw 21 to provide protection and containment of the operative elements of the cartridge.

The body 17 of cartridge housing 13 is generally of box-shaped configuration, and near front vertical wall 23 thereof, a recess 25 is formed. The recess 25 extends vertically through the body 17 near its front end, opening into the top wall 27 (FIG. 2) and bottom wall 29 (FIG. 1) to facilitate the placement and operationof ceramic transducer and coupling subassembly 31 in the body 17.

Turning now to an important aspect of my invention which concerns itself with an improved transducer arrangement that effectively maintains separation of two 'stcreophonic signals, attention is further directed to proved stereo pickup cartridge which employs a pair of transducer elements arranged in such a manneras to enable the cartridge to have a relatively short length.

A further object of my invention is to provide a stereo pickup cartridge which employs a novel arrangement of a pair of transducer elements and a coupler.

In carrying out my invention in one form thereof, I utilize a pair of ceramic transducer elements which are arranged in spaced apart and crosswise relationship. These transducer elements are connected to co-operating sections of a resilient coupler. The coupler is constructed and arranged with respect to a drive rod so that it transmits each one of the stereophonic signals of a record groove to an associated one of the transducer elements with maximal separation of the two signals.

Further aspects of my invention will become apparent hereinafter, and the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which I regard as my invention, The invention, however, as to organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a stereo phonograph pickup cartridge embodying one form of my invention,

with part of the housing broken away to show the overall construction;

FIG. 2 is a perspective view similar to FIG. l, but

with the cover and transducer assembly removed to show interior detail of the cartridge housing;

FIG. 3 is a plan view of the cartridge of FIG. 1, cmbodying my invention, with dotted lines showing the transducer and coupling assembly therein;

FIG. 4 is a side elevation view of the cartridge of FIG. 1, with dotted lines delineating the transducer and coupling assembly, and part of the drive rod assembly;

FIG. 5 is a sectional view taken generally along the line 5-5 of FIG. 3.

FIG. 1. As shown-therein, the subassembly 31 includes a pair of elongated ceramic transducer elements 33 and 35 arranged in spaced apart proximity and crisscross fashion with respect to each other. The transducer elements 33 and 35 are the type of generators which use the bender mode of operation and each of the these elements includes two relatively thin strips of ceramic material, such as, for example, barium titanate (which with suitable materials between them have been bonded together).

As further shown in FIG. 1, the elements 33 and 35 are in the shape of elongated relatively flat bars disposed in edgewise relationship with each other, and

each bar at 45 degrees from the horizontal. More particularly,-these elements are generally disposed in planes that are in perpendicular, crisscross, and spaced apart relationship. At their upper ends 37 and 39, respectively, elements 33 and 35 are suitably connected by wires (not shown) to terminal pins 41 to 44 on terminal block 19 at the rear of the cartridge housing 13. The upper ends 37 and 39 of the transducer elements 33 and 35 are extended through, ensconced in and secured to associated resilient blocks 47 and 49, which are suitably supported within the housing, such as, for example, by compressive engagement with angular body walls such as wall 51, shown in FIG. 1 and 5. 'The lower ends 57 and 59 of the ceramic transducer elements 33 and 35 cooperalively engage coupler 61, being bonded thereto to mechanically link drive rod 63 to the elements.

The drive rod or tube 63 is secured to, carried by, and extends forwardly from resilient block 65 (as best shown in FIG. 4). The front end 67 of the drive rod 65 of the illustrated embodiment of my invention is bent downwardly and then forwardly, being flattened at the extreme end, which has a single stylus 69 extending downwardly therefrom. For the type of drive rod illustrated by way of example in FIG. 1, it is understood that the supported end of the rod must be rigidly held in such a manner as to prevent any undesirable movement thereof. It is also understood that a drive rod having its free end in general axial alignment with a main body portion (i.e., a straight rod type) may also be advantageously used with my invention.

The coupler 61 is preferably formed from a rubber like material, such as, for example, butyl rubber, which mate-' shown in FIG. 5, the body portion 71 of the coupler includes a curved section 75 on its bottom surface. The bottom surface of coupler body 71 also includes a pair of planar sections 77, 79 extending outwardly in tangential fashion from opposite sides of the curved section 75.

From the upper surfaceof the body portion 71 of coupler 61, the arms 73 and 74 extend radially outwardly in divergent fashion from the axis of curvature of curved section 75 of body 71, each arm being disposed at an angle of approximately 45 degrees relative to the horizontal. (See FIG. 5.) In addition, the arms 73, 74 are spaced apart or offset in a direction parallel to the long axis of the drive rod 63. At the outer end of each of the arms 73 and 74, there is integrally formed a pair of clamping fingers 81. Each pair of fingers 81 extends inwardly and upwardly, being perpendicular to its associated arm, and has a slot 83 therebetwcen. Between each pair of clamping fingers 8] there is positioned and secured in the slot 83, an associated end 57 or elements 33 and 35.

Turning now to an explanation of the operation of my stereo phonograph pickup cartridge 11, attention is directed to FIG. 1. The pickup cartridge 11 may be effectively used to play a stereophonic record of the type having two stereophonically related signals recorded on the separate walls of the record groove. These walls are at an included angle of 90 degrees and each wall is at a 45 degree angle with respect to the vertical. Undulations on one Wall of the groove will vibrate the drive rod 63 in a direction along the longitudinal axis of coupler arm 73, and undulations of the other wall of the record groove will vibrate the drive rod 63 in a direction along the longitudinal axis of the coupler arm 74. As the coupler arm 73 vibrates in a direction along its longitudinal axis, it thereupon actuates bottom end 57 of its associated transducer element 33, to convert the mechanical undulations of one wall of the record groove into electrical energy components. The mechanical forcesfrom coupler arm 73 are imparted to transducer element 33 in a direc- 59 of one of the transducer tion perpendicular to both the longitudinal axis and flat side of the element. As the coupler arm 74 vibrates in a direction along its longitudinal axis, it thereupon actuates bottom end 59 of its associated transducer element 35, to convert the mechanical undulations of the other wall of the record groove into electrical energy components. The mechanical forces from coupler arm 74 are imparted to transducer element 35 in a direction perpendicular to both the longitudinal axis and fiat side of the element.

With such an arrangement, the desired vibratory forces.

for actuating each transducer element (eg. element 33) are transmitted to that element along the longitudinal axis of its associated coupler arm (e.g. arm 73). The arms.

73 and 75 are constructed so that they are relatively stiff in their longitudinal direction and they therefore readily transmit the desired vibratory forces to their associated transducer elements. However, arms 73 and 75 are each also readily bendable in response to vibratory forces which are generally transverse to their longitudinal axes, such as, for example, undesirable vibratory forces intended for transmission by the other coupler arm. Thus, for example, the undulations on one wall of a stereophonic record groove will vibrate drive rod 63 in a direction along the longitudinal axis of coupler arm 73 to readily actuate transducer element 33, but these same undulations will have a minimal effect upon coupler arm 74, since they are in a perpendicular direction thereto.

As is well known in the art, the transducer elements 33 and 35 are each connected to one channel of an amplifier stage to effect suitable amplification of the two stereophonic signals to separate loudspeaker systems.

In view of the structural arrangement of the ceramic transducer elements 33 and 35, and their coupling to the drive rod 63, maximum coupling efficiency is achieved for actuating each of the transducer elements by the undulations of its associated record groove wall, thereby achieving an enhanced separation of the stereophonic signals.

It will now, therefore, be seen that I have provided an improved stereophonic pickup cartridge which is simplified in construction and includes a novel and effective means for maintaining separation of the stereophonic signals.

While, in accordance with the patent statues, I have described what at present is considered to be the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from my invention and I, therefore, aim in the following claims to cover all such equivalent variations as fall within the true spirit and scope of this invention.

What I claim and desire to secure by Letters Patent of the United States is:

l. A stereo phonograph pickup cartridge comprising a housing, a stylus assembly including a drive rod supported within said housing, a pair of elongated ceramic type transducer elements arranged in spaced apart and criss-cross relationship within said housing. and resilient coupling means for connecting said drive rod to each of said transducer elements in such a manner that an effective segregation of a pair of stereophonic signals is thereby achieved.

2. A stereo phonograph pickup cartridge comprising a housing, a stylus assembly including a drive rod sup-' ported within said housing, a pair of elongated transducer elements arranged in spaced apart and crisscross relationship within said housing, said transducer elements being disposed in generally edgewise relationship and having their longitudinal axes disposed transversely in said cartridge housing, and resilient coupling means for connecting said drive rod to each of said transducer ele ments in such a manner that an effective segregation of a pair of stereophonic signals is thereby achieved.

3. A stereo phonograph pickup cartridge comprising a housing, a stylus assembly including an elongated drive rod supported within said housing, a pair of elongated transducer elements arranged in spaced apart and crisscross relationship within said housing, said transducer elements being disposed in generally edgewise relationship and having their longitudinal axes arranged in generally perpendicular relationship to the longitudinal axis of said drive rod, and a resilient coupler for connecting said drive rod to each of said transducer elements, said coupler including a curved section for engaging said-drive rod, and a pair of outstretched elongated arms each of which is directly connected to one end of an associated transducer element and in perpendicular relationship thereto, each of said arms being adapted to transmit vibrations to its associated transducer element which are directed along the longitudinal axes of said arm by said drive rod.

4. A stereo phonograph pickup cartridge comprising a housing, a stylus assembly including an elongated drive rod supported within said housing, a pair of elongated transducer elements arranged laterally in spaced apart and crisscross relationship within a lateral recess formed near one end of said housing, said transducer elements 7 being generally disposed in planes that are in perpendicularv relationship, said planes being in parallel relationship to the longitudinal axis of said drive rod, and a resilient coupler for connecting said drive rod to each of said transducer elements, said coupler including a curved section for engaging said drive rod, and a pair of outstretched elongated and longitudinally offset arms. each of said arms being directly connected to one end of an associated transducer element and in perpendicular relationship thereto, each said arm being adapted to transmit vibrations to its associated transducer element which are directed along the longitudinal axis of said arm by said drive rod.

5. The pickup cartridge of claim 4 wherein the resilient coupler is constructed of butyl rubber.

References Cited by the Examiner UNITED STATES PATENTS 2,565,586 8/1951 Bauer l79100.4l

6 3,040,136 6/1962 Grado 179 100.41 3,056,861 10/1962 Grover 179-10041 3,196,216 7/1965 Davis 179-40041 FOREIGN PATENTS 1,269,429 7/1961 France.

10 NORTON ANSHER, Primary Examiner.

CLIFFORD B. PRICE, Assistant Examiner. 

1. A STEREO PHONOGRAPH PICKUP CARTRIDGE COMPRISING A HOUSING, A STYLUS ASSEMBLY INCLUDING A DRIVE ROD SUPPORTED WITHIN SAID HOUSING, A PAIR OF ELONGATED CERAMIC TYPE TRANSDUCER ELEMENTS ARRANGED IN SPACED APART AND CRISS-CROSS RELATIONSHIP WITHIN SAID HOUSING, AND RESILIENT COUPLING MEANS FOR CONNECTING SAID DRIVE ROD TO EACH OF SAID TRANSDUCER ELEMENTS IN SUCH A MANNER THAT AN EFFECTIVE SEGREGATION OF A PAIR OF STEREOPHONIC SIGNALS IS THEREBY ACHIEVED. 